Not able to run SSIS package from Stored Procedure

I created an ssis package. It runs fine when i run it from command prompt. But when i run it from query analyser using xp_cmdshell, it gives the error below

Description: Failed to decrypt protected XML node "DTS:Password" with error 0x8009000B "Key not valid for use in specified state.". You may not be authorized to access this information. This error occurs when there is a cryptographic error. Verify that

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